Single battery and battery pack

Abstract

The utility model discloses a single battery and a battery pack, and belongs to the technical field of batteries. Each single battery comprises a cover plate assembly and an electrode assembly, and the electrode assembly is arranged on one side of the cover plate assembly in the thickness direction; the cover plate assembly comprises a cover plate body, a pole and a connecting sheet, wherein the cover plate body is provided with an assembling hole; the pole is arranged on one side, deviating from the electrode assembly, of the cover plate body, and the pole is provided with a first convex part which is convexly arranged towards the assembling hole; the connecting piece is arranged on the side, facing the electrode assembly, of the cover plate body and comprises a connecting part and a step part which are connected, the connecting part is connected with the electrode assembly, and the step part partially penetrates through the assembly hole and is provided with a through hole in the thickness direction; the first convex part penetrates through the through hole and is connected with the step part; and the pole and the step part jointly clamp two sides of the cover plate body along the thickness direction. The cover plate body is clamped through the cooperation of the connecting piece and the pole, and a stable electrical connection path is formed among the tabs, the connecting piece and the pole, so that the contact resistance is reduced, and the assembly efficiency and the production yield are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a single battery and a battery pack. BACKGROUND

[0002] The structural member of a lithium ion battery is one of important components of a lithium ion power battery, and various connection relationships exist in the structural member, and the sealing performance and the overcurrent performance need to be considered.

[0003] The connecting sheet is usually a sheet-shaped structure with good conductivity and certain flexibility, the cover plate assembly cannot be formed in one process during the assembly of the pole, and the connecting sheet and the pole still need to be fixed and connected, and the assembly process is complicated. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims to overcome the technical problem that the assembly process of the connecting sheet and the pole is complicated, and another object of the utility model is to provide a battery pack.

[0005] TECHNICAL SCHEME: The utility model discloses a single battery, which comprises a cover plate assembly and an electrode assembly, the electrode assembly is arranged on one side of the cover plate assembly along the thickness direction, and the electrode assembly comprises a tab.

[0006] The cover plate assembly comprises:

[0007] The cover plate body has an assembly hole.

[0008] The pole is arranged on the side of the cover plate body away from the electrode assembly, and the pole has a first protruding part protruding towards the inside of the assembly hole.

[0009] The connecting sheet is arranged on the side of the cover plate body facing the electrode assembly, and the connecting sheet comprises a connecting part and a stepped part connected with each other, the connecting part is connected with the tab, the stepped part is partially arranged in the assembly hole, and a through hole is formed in the thickness direction.

[0010] The first protruding part penetrates the through hole and is connected with the stepped part, and the pole and the stepped part jointly clamp the two sides of the cover plate body along the thickness direction.

[0011] In some embodiments, the stepped part comprises a first step, a second step and a third step arranged along the thickness direction, the first step is arranged in the assembly hole, the third step surrounds the assembly hole and is located on the side of the cover plate body facing the electrode assembly, and the second step surrounds and connects the first step and the third step.

[0012] The through hole penetrates the first step, the second step and the third step.

[0013] In some embodiments, the cover plate assembly further comprises a sealing member, the sealing member comprising a first sealing segment, a second sealing segment and a third sealing segment, the first sealing segment being clamped between the pole column and the second step, the third sealing segment being clamped between the third step and the cover plate body, and the second sealing segment being arranged in the assembly hole and connected with the first sealing segment and the third sealing segment respectively.

[0014] In some embodiments, the second step is partially arranged in the assembly hole, and along the thickness direction, the portion of the second step arranged in the assembly hole has a first size H1 mm, satisfying 0.5≤H1≤0.8.

[0015] In some embodiments, along the thickness direction, the second step has a second size H2 mm from the pole column, and the third step has a third size H3 mm from the cover plate body, satisfying 0.5≤H2≤0.7 and 0.5≤H3≤0.7.

[0016] In some embodiments, the width direction of the cover plate assembly intersects with the thickness direction, and along the width direction of the cover plate assembly, the first step has a fourth size W1 mm, satisfying 2.5≤W1≤5.

[0017] The second step has a fifth size W2 mm, satisfying 5≤W2≤7.5.

[0018] In some embodiments, the stepped portion has a first surface facing the electrode assembly and a second surface away from the electrode assembly, the through hole penetrates the first surface and the second surface, and the stepped portion has a relief groove arranged on the first surface and communicating with the through hole.

[0019] The relief groove has a groove wall opposite to the second surface, and along the thickness direction, the second surface and the groove wall have a minimum distance T mm, satisfying 1.2≤T≤1.8.

[0020] In some embodiments, the connecting portion is arranged spaced apart from the cover plate body, and along the thickness direction, the connecting portion has a thickness size T1 mm, satisfying 0.5≤T1≤0.8.

[0021] In some embodiments, the pole column comprises a first column body and a second column body connected with each other, the first column body is located on the side of the cover plate body away from the electrode assembly, the second column body is located between the first column body and the connecting sheet and partially arranged in the assembly hole, and the first protrusion is arranged on the side of the second column body away from the first column body.

[0022] The application further discloses a battery pack comprising the single battery as described in the above embodiments.

[0023] Beneficial effects: the single battery in the embodiment of the application is connected with the tab through the connecting part of the connecting piece, and the first protruding part of the pole penetrates the through hole of the connecting piece step part and is connected with the step part, so that a stable electrical connection path is formed between the tab, the connecting piece and the pole, the contact resistance is reduced, the stability and reliability of current transmission are ensured, and the risk of battery performance decline or failure caused by poor connection is reduced. In addition, the pole and the step part are clamped on both sides of the cover plate body along the thickness direction, the space of the cover plate assembly is fully utilized, the structure of the single battery is more compact, which is beneficial to the miniaturization design of the battery and improves the energy density of the battery; when the battery is subjected to external force, the above structure can better disperse stress and prevent the cover plate body from deforming or being damaged, thereby improving the mechanical stability and service life of the single battery. When assembling, only the step part of the connecting piece is inserted into the assembly hole, and then the first protruding part of the pole is inserted into the through hole and fixedly connected (such as welding), so that the assembly of the pole, the connecting piece and the cover plate body can be completed, the production efficiency is improved, and the assembly cost is reduced.

[0024] The battery pack of the embodiment of the application comprises the single battery as described in the above embodiment. Therefore, all the technical features and technical effects of the single battery described above can be had, which will not be described here again. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 It is a schematic view of the three-dimensional structure of the single battery of the embodiment of the application.

[0027] Figure 2 It is a schematic view of the top view structure of the single battery of the embodiment of the application.

[0028] Figure 3 It is Figure 2 the sectional view in direction A-A.

[0029] Figure 4 It is Figure 3 the local enlarged view at B.

[0030] Figure 5 It is a schematic view of the cooperation of the cover plate body and the connecting piece in the single battery of the embodiment of the application.

[0031] Figure 6Fig. 3 is a schematic view of a perspective structure of two connecting pieces in a single battery according to an embodiment of the present application, one of which is connected with a positive pole post and the other of which is connected with a negative pole post;

[0032] Figure 7 Fig. 4 is a schematic view of a perspective structure of two connecting pieces in a single battery according to an embodiment of the present application, from another perspective;

[0033] Label explanation: 1, cover plate assembly; 2, electrode assembly; 21, tab; X, thickness direction; 11, cover plate body; 110, assembly hole; 12, pole post; 120, first protruding part; 13, connecting piece; 131, connecting part; 132, stepped part; 1320, through hole; 1321, first step; 1322, second step; 1323, third step; 14, sealing piece; 141, first sealing section; 142, second sealing section; 143, third sealing section; Y, width direction; 1325, first surface; 1326, second surface; 1327, avoiding groove; 1328, groove wall; 121, first cylinder; 122, second cylinder;

[0034] 15, upper plastic. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0036] In the description of the present application, it should be understood that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or components referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, the meaning of "multiple" is two or more, at least one of which can be one, two or more, unless otherwise explicitly specified. The terms "first", "second", "third" and the like are only for the convenience of description and naming of parts or embodiments, and do not imply an important order between the parts or between the embodiments.

[0037] It should also be noted that in the drawings of the present application, the arrow marked X indicates the thickness direction, and the arrow marked Y indicates the width direction. In the description of the present application, the thickness direction and the width direction are introduced to more clearly define the structure and relative positional relationship of the components in the single battery.

[0038] As a preamble of the embodiments of the present application, the structural member of the lithium ion battery is an important component of the lithium ion power battery. There are various connection relationships inside the structural member, and the requirements of sealing performance and overcurrent performance need to be considered at the same time. The connecting piece is usually a metal sheet structure with good conductivity and certain flexibility. The cover plate assembly cannot be processed in one step during the assembly process of the pole column, and the connecting piece still needs to be fixedly connected with the pole column. The assembly process is complicated, the product has high internal resistance, the production efficiency and yield are low, and the cost is high. After the tab in the battery is connected with the connecting piece, the tab needs to be bent during the assembly process of the cover plate assembly and the shell. The tab occupies a large internal space of the battery, the space utilization rate of the battery is low, the length of the bent part of the tab is long, and the risk of tearing exists, the product performance is reduced, and the competitiveness is insufficient.

[0039] Therefore, the embodiments of the present application provide a single battery, which aims to solve at least one of the above technical problems.

[0040] Please refer to Figures 1 to 7As shown, the single battery provided by the embodiment of the present application comprises a cover plate assembly 1 and an electrode assembly 2, the electrode assembly 2 is arranged on one side of the cover plate assembly 1 along the thickness direction X, and the electrode assembly 2 comprises a tab 21; the cover plate assembly 1 comprises a cover plate body 11, a post 12 and a connecting sheet 13; the cover plate body 11 has an assembly hole 110; the post 12 is arranged on the side of the cover plate body 11 away from the electrode assembly 2, and the post 12 has a first protrusion 120 protruding towards the inside of the assembly hole 110; the connecting sheet 13 is arranged on the side of the cover plate body 11 towards the electrode assembly 2, and the connecting sheet 13 comprises a connecting portion 131 and a stepped portion 132 connected together, the connecting portion 131 is connected with the tab 21, the stepped portion 132 partially penetrates the assembly hole 110, and a through hole 1320 is formed in the stepped portion 132 along the thickness direction X; the first protrusion 120 penetrates the through hole 1320 of the stepped portion 132 and is connected with the stepped portion 132, and the post 12 and the stepped portion 132 jointly sandwich the two sides of the cover plate body 11 along the thickness direction X. It should be understood that, by connecting the connecting portion 131 of the connecting sheet 13 with the tab 21, and penetrating the first protrusion 120 of the post 12 through the through hole 1320 of the stepped portion 132 of the connecting sheet 13 and connecting the first protrusion 120 with the stepped portion 132, a stable electrical connection path is formed between the tab 21, the connecting sheet 13 and the post 12, the contact resistance is reduced, the stability and reliability of current transmission are ensured, and the risk of battery performance degradation or failure caused by poor connection is reduced. In addition, the post 12 and the stepped portion 132 jointly sandwich the two sides of the cover plate body 11 along the thickness direction X, the space of the cover plate assembly 1 is fully utilized, the structure of the single battery is more compact, which is conducive to the miniaturization design of the battery and improves the energy density of the battery; the mechanical strength of the cover plate assembly 1 of the present application is high, when the battery is subjected to external force, the stress can be better dispersed, and the deformation or damage of the cover plate body 11 is prevented, thereby improving the mechanical stability and service life of the single battery. During assembly, only the stepped portion 132 of the connecting sheet 13 is inserted into the assembly hole 110, and then the first protrusion 120 of the post 12 is inserted into the through hole 1320 and fixedly connected (such as welding), the assembly between the post 12, the connecting sheet 13 and the cover plate body 11 can be completed, the production efficiency is improved, and the assembly cost is reduced.

[0041] In some embodiments, the first protrusion 120 penetrating the through hole 1320 and being connected with the stepped portion 132 can be a welding connection, and at the same time, the first protrusion 120 and the stepped portion 132 can be riveted. Specifically, a rivet structure is arranged at the end of the first protrusion 120 of the post 12, after the first protrusion 120 penetrates the through hole 1320, the rivet structure at the end of the first protrusion 120 is deformed by a riveting tool, so that the first protrusion 120 and the stepped portion 132 are tightly connected together. This riveting method has the advantages of fast connection speed, high connection strength and less false welding.

[0042] Specifically, after the first protruding part 120 of the pole 12 is inserted through the through hole 1320, a riveting hole (not shown in the figure) can be formed at the end of the first protruding part 120 by extrusion, so that the end of the first protruding part 120 is in interference fit with the stepped part 132, preliminarily realizing the positioning and assembly of the first protruding part 120 and the connecting sheet 13, strengthening the positioning stability and connection, and improving the connection sealing performance to some extent. The friction generated by the interference fit can effectively prevent the relative displacement of the pole 12 and the connecting sheet 13 due to factors such as vibration and temperature change during the operation of the battery, ensuring that the pole 12 and the connecting sheet 13 always maintain accurate relative positions, thereby ensuring the stability of the overall structure of the battery and the reliability of the electrical connection. The preliminary positioning and assembly is realized by extruding the riveting hole, which simplifies the entire assembly process. Without additional complex positioning tools or tedious adjustment steps, the operator only needs to perform a simple extrusion operation after inserting the first protruding part 120, which can quickly realize preliminary positioning, greatly improve assembly efficiency, reduce labor costs, and also facilitate large-scale automated production.

[0043] Specifically, the material of the connecting sheet 13 can be selected and optimized according to the specific use scenarios and performance requirements of the battery. For example, for batteries that require high conductivity and corrosion resistance, pure copper or copper alloy can be selected as the material of the connecting sheet 13.

[0044] Specifically, the shape of the first protruding part 120 and the through hole 1320 can be optimized according to actual needs. For example, the first protruding part 120 is designed as a polygon (such as a hexagon), and the through hole 1320 is also correspondingly hexagonal, which can increase the friction between the two to prevent relative rotation during use. Alternatively, the first protruding part 120 can be designed in a shape with a groove, and a protrusion matching the groove is provided in the through hole 1320, which further enhances the stability and reliability of the connection through this concave-convex matching method. Alternatively, the first protruding part 120 can be designed as a taper, which can better fit with the stepped part 132 when inserted through the through hole 1320, increasing the tightness of the connection. In addition, the outer surface of the pole 12 can be provided with some anti-slip textures to facilitate easier operation when installing and removing the pole 12.

[0045] In some embodiments, the connecting part 131 and the stepped part 132 of the connecting sheet 13 can be separated (not shown in the figure). During assembly, different specifications of the connecting part 131 and the stepped part 132 can be selected and combined according to the different positions and shapes of the tabs 21, and the modular structure design of the connecting sheet 13 improves the versatility and flexibility of the connecting sheet 13, which can adapt to the assembly needs of different types of single batteries, reducing production costs.

[0046] Please refer to Figure 4 and Figure 6As shown, in some embodiments, the stepped portion 132 includes a first step 1321, a second step 1322 and a third step 1323 arranged along the thickness direction X, the first step 1321 is arranged in the assembly hole 110, the third step 1323 surrounds the assembly hole 110 and is located on the side of the cover plate body 11 facing the electrode assembly 2, the second step 1322 surrounds and connects the first step 1321 and the third step 1323; the through hole 1320 penetrates the first step 1321, the second step 1322 and the third step 1323. It should be understood that by designing the stepped portion 132 with a multi-step structure, the contact area between the connecting piece 13 and the cover plate body 11 is significantly increased. The first step 1321 is arranged in the assembly hole 110 and forms a positioning fit with the first protrusion 120 of the pole 12, which can accurately position the installation position of the connecting piece 13 and prevent it from shaking or deviating in the assembly hole 110; the second step 1322 surrounds and connects the first step 1321 and the third step 1323, which increases the overall structural strength of the connecting piece 13; the third step 1323 surrounds the assembly hole 110 and is located on the side of the cover plate body 11 facing the electrode assembly 2, which further increases the contact area with the cover plate body 11 and makes the connection between the connecting piece 13 and the cover plate body 11 more stable. The first protrusion 120 of the pole 12 penetrates the through hole 1320 formed in the stepped portion 132, which can better achieve a close connection with the connecting piece 13, thereby ensuring the stability of the entire electrical connection system. At the same time, the stepped portion 132 with a multi-step structure can more effectively disperse various stresses received by the battery during use, and when the battery is subjected to external mechanical forces, different steps can bear and transmit stresses respectively, avoiding stress concentration in a certain part, thereby reducing the possibility of damage to the cover plate body 11 or the connecting piece 13 due to stress concentration.

[0047] It also needs to be understood that the through hole 1320 penetrates the first step 1321, the second step 1322 and the third step 1323 in the thickness direction X, which can provide heat dissipation channels on the one hand, so that the heat generated inside the battery can be conducted to the outside through these channels, improving the heat dissipation performance of the battery; on the other hand, the through hole 1320 can provide an observation channel during the assembly of the pole 12 and the connecting piece 13, which facilitates the operator to view the position and state of the first protruding part 120 of the pole 12 in real time, ensuring the accuracy of the assembly. Furthermore, the fixed connection of the first protruding part 120 of the pole 12 and the connecting piece 13 needs to be realized through the through hole 1320. When the welding method is adopted, the operator can directly weld the connection part of the first protruding part 120 and the stepped part 132 through the through hole 1320, ensuring the accuracy of the welding position and the sealing performance of the connection position of the pole 12 and the connecting piece 13, avoiding problems such as virtual welding and missed welding, so as to ensure that the current can be stably and efficiently conducted between the pole 12 and the connecting piece 13, reduce the contact resistance, and improve the overall performance of the battery. When the riveting process is adopted, the through hole 1320 provides an operation space for the riveting tool, so that the rivet can smoothly pass through the first protruding part 120 and the stepped part 132, and after riveting deformation, the two are firmly fixed together. In addition, the through hole 1320 also provides convenience for subsequent quality detection, and the detection personnel can use professional tools to detect the connection part of the pole 12 and the connecting piece 13 through the through hole 1320, such as flaw detection, sealing detection, etc., to ensure that the connection quality meets the standard, and to ensure the reliability and safety of the single battery.

[0048] Please refer to Figure 4As shown, in some embodiments, the cover plate assembly 1 further comprises a sealing member 14, which includes a first sealing segment 141, a second sealing segment 142, and a third sealing segment 143. The first sealing segment 141 is clamped between the pole post 12 and the second step 1322, the third sealing segment 143 is clamped between the third step 1323 and the cover plate body 11, and the second sealing segment 142 is inserted into the assembly hole 110 and connected with the first sealing segment 141 and the third sealing segment 143 respectively. It should be understood that the three-segment sealing structure design can seal the assembly hole 110 and its surrounding area in all directions. The first sealing segment 141 clamped between the pole post 12 and the second step 1322 can effectively prevent liquid or gas from entering the battery interior from the connection part of the pole post 12 and the connecting piece 13; the third sealing segment 143 clamped between the third step 1323 and the cover plate body 11 can prevent impurities, moisture and the like from the contact surface of the connecting piece 13 and the cover plate body 11 from entering; and the second sealing segment 142 inserted into the assembly hole 110 and connected with the first sealing segment 141 and the third sealing segment 143 forms a continuous sealing path, greatly improving the integrity and reliability of the sealing, ensuring the stability of the battery interior environment, preventing the leakage of electrolyte in the battery interior and the intrusion of external substances, thereby prolonging the service life of the battery and ensuring its performance stability. The sealing member 14 not only plays a sealing role, but also can enhance the mechanical properties of the battery structure to a certain extent. When the battery is subjected to external vibration or impact, the sealing member 14 can act as a buffer medium to absorb part of the impact force, reduce the relative displacement and friction between the pole post 12, the connecting piece 13 and the cover plate body 11, and reduce the risk of component damage. The sealing member 14 is usually made of insulating material, which can not only realize the sealing function, but also improve the electrical insulation performance of the battery interior. Especially at the connection parts between the pole post 12 and the connecting piece 13, and between the connecting piece 13 and the cover plate body 11, the sealing member 14 can effectively isolate components of different potentials to prevent electrical short circuit and ensure the electrical safety of the battery.

[0049] It should also be understood that the sealing member 14 with a three-segment structure and the stepped part 132 with a multi-step structure are convenient for each other during assembly, which improves the assembly efficiency and reduces the assembly error.

[0050] Please refer to Figure 4As shown, in some embodiments, the second step 1322 is partially arranged in the assembly hole 110, and along the thickness direction X, the portion of the second step 1322 arranged in the assembly hole 110 has a first size H1 mm, satisfying 0.5≤H1≤0.8. It should be understood that by setting the thickness size of the second step 1322 arranged in the assembly hole 110 within the range of 0.5mm to 0.8mm, precise assembly positioning between the connecting piece 13 and the cover plate body 11 is achieved, so that the second step 1322 tightly fits the inner wall of the assembly hole 110, neither easily loosens nor shifts the connecting piece 13, affecting the stability of electrical connection and the reliability of the battery structure; nor increases the assembly difficulty, and even may damage the cover plate body 11 or the connecting piece 13. At the same time, the above size range helps to optimize the overall mechanical strength and stress distribution of the battery, the second step 1322 can effectively transmit the external force received by the battery to the cover plate body 11, and itself can also withstand a certain stress, when the battery is subjected to vibration or impact, the second step 1322 can play a buffering and supporting role, ensuring the integrity of the battery structure. Furthermore, the appropriate insertion depth can make the second sealing section 142 of the sealing member 14 better cooperate with the second step 1322 and the inner wall of the assembly hole 110, thereby improving the sealing performance and effectively preventing external substances from entering the battery interior and preventing the battery interior substances from leaking.

[0051] Specifically, H1 can be any value or a range value between two values in 0.5mm, 0.6mm, 0.7mm and 0.8mm. It should be understood that when H1 is closer to 0.5mm, the thickness size of the second sealing section 142 is the smallest, the sealing member 14 is more lightweight, and the connection stability and sealing performance of the connecting piece 13, the cover plate body 11, the sealing member 14 and the pole 12 are reduced; when H1 is closer to 0.8mm, the connection stability and sealing performance are better.

[0052] Please refer to Figure 4As shown, in some embodiments, along the thickness direction X, the second step 1322 has a second size H2 mm away from the pole column 12, and the third step 1323 has a third size H3 mm away from the cover plate body 11, satisfying: 0.5≤H2≤0.7; 0.5≤H3≤0.7. It needs to be understood that by setting the thickness size of the second step 1322 away from the pole column 12 to limit the size of the first sealing section 141 after compression, and by limiting the thickness size of the third step 1323 away from the cover plate body 11 to limit the size of the third sealing member 14 after compression, on the one hand, the stable compression size can ensure that the sealing member 14 maintains good sealing performance during long-term use, reducing the risk of sealing failure due to aging and elastic attenuation of the sealing member 14. On the other hand, such precise size control also facilitates ensuring the consistency of sealing performance and improving the stability of product quality in different production batches. In actual application, different battery operating environments have different performance requirements for the sealing member 14. For example, in a high-temperature environment, the material of the sealing member 14 may expand due to heat, at which time a reasonable size range can reserve a certain space so that the sealing member 14 can still maintain an effective sealing state after thermal expansion and is not damaged due to excessive extrusion. In a low-temperature environment, the elasticity of the sealing member 14 may decrease, and a suitable compression size can ensure that the sealing member 14 can still tightly fit the surface of the component even in the case of decreased elasticity, preventing the intrusion of external substances.

[0053] Specifically, H2 can be any value or a range value between two values in 0.5 mm, 0.6 mm and 0.7 mm. H3 can be any value or a range value between two values in 0.5 mm, 0.6 mm and 0.7 mm. By limiting H2 and H3 in the above range, the sealing member 14 can exert the best sealing and insulation effect at the corresponding position, and play a role in buffering and dispersing stress when subjected to mechanical force, thereby enhancing the mechanical strength and reliability of the battery as a whole. When H2 and H3 are closer to 0.5 mm, the thickness size of the first sealing section 141 and the third sealing section 143 is the smallest, the sealing member 14 is more lightweight, and the stability and sealing performance of the connection among the connecting sheet 13, the cover plate body 11, the sealing member 14 and the pole column 12 decrease; when H2 and H3 are closer to 0.7 mm, the stability and sealing performance of the connection are better.

[0054] Please refer to Figure 4As shown, in some embodiments, the width direction Y of the cover plate assembly 1 intersects with the thickness direction X, along the width direction Y of the cover plate assembly 1, the first step 1321 has a fourth size W1 mm, satisfying 2.5≤W1≤5; the second step 1322 has a fifth size W2 mm, satisfying 5≤W2≤7.5. It needs to be understood that by limiting W1 in the above range, it is ensured that there is sufficient relative support area between the step portion 132 and the assembly hole 110 when the step portion 132 is arranged in the assembly hole 110. When the battery is impacted by external force or vibrated, the larger support area can better disperse stress, prevent the first step 1321 from shaking or shifting in the assembly hole 110, and thus ensure the stability of the connection between the connecting piece 13 and the cover plate body 11, and maintain the stability of the entire battery structure. By limiting W2 in the above range, on the one hand, the structural strength of the connecting piece 13 itself is enhanced, so that it is not easy to deform when transmitting current and bearing external force; on the other hand, the wider second step 1322 also provides a wider installation and action space for the sealing element 14, which is conducive to improving the sealing effect of the sealing element 14 and reducing the risk of foreign matter and moisture entering the inside of the battery.

[0055] Specifically, W1 can be any value or a range value between two values in 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm and 5.0 mm. W2 can be any value or a range value between two values in 5 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm and 7.5 mm. When W1 is closer to 2.5 mm and W2 is closer to 5 mm, the overall volume and weight of the battery are lighter under the premise of meeting the overcurrent capacity and sealing performance; when W1 is closer to 5.0 mm and W2 is closer to 7.5 mm, the connecting piece 13 can provide better structural support and sealing performance.

[0056] Please refer to Figures 4 to 7As shown, in some embodiments, the stepped portion 132 has a first surface 1325 facing the electrode assembly 2 and a second surface 1326 facing away from the electrode assembly 2, the through hole 1320 penetrates the first surface 1325 and the second surface 1326, the stepped portion 132 has an avoidance groove 1327, the avoidance groove 1327 is arranged on the first surface 1325 and communicates with the through hole 1320; the avoidance groove 1327 has a groove wall 1328, the groove wall 1328 is opposite to the second surface 1326, and between the second surface 1326 and the groove wall 1328 in the thickness direction X, there is a minimum distance T mm, which satisfies: 1.2≤T≤1.8. It needs to be understood that by arranging the avoidance groove 1327, on the one hand, it provides more convenient space for the connection operation of the pole 12 and the connecting piece 13, improves the assembly efficiency, and reduces the connection defects caused by insufficient operation space. When the first protruding portion 120 penetrates the through hole 1320 and is connected with the stepped portion 132, the avoidance groove 1327 can accommodate the excess material that may be generated in the process, avoiding the accumulation of excess material at the connection site to affect the connection quality and appearance. On the other hand, it reduces the weight of the cover plate assembly 1, which helps to realize the miniaturization and lightweight design of the battery. In addition, the avoidance groove 1327 can provide an additional heat dissipation channel, so that heat can be dissipated more effectively, which helps to improve the heat dissipation efficiency of the battery, reduce the temperature inside the battery, prolong the service life of the battery and improve its performance. By controlling the minimum distance T between the second surface 1326 and the groove wall 1328, i.e. controlling the minimum distance between the first surface 1325 of the stepped portion 132 and the groove wall 1328 of the avoidance groove 1327 to be between 1.2 mm and 1.8 mm, it helps to ensure the connection strength of the stepped portion 132 and the first protruding portion 120, and ensures the connection stability between the pole 12 and the connecting piece 13, so as to maintain the structural strength of the stepped portion 132 while ensuring the function of the avoidance groove 1327, enhance the connection reliability, and ensure the stability of the electrical connection during the use of the battery.

[0057] Specifically, T can be any value or a range value between two values in 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm and 1.8 mm. When T is closer to 1.2 mm, the connecting piece 13 is lighter in weight, the structural strength of the connection position of the stepped portion 132 and the first protruding portion 120 decreases, affecting the connection stability between the pole 12 and the connecting piece 13; when T is closer to 1.8 mm, the overall size of the connecting piece 13 increases, the structural stability of the stepped portion 132 decreases slightly, and it is not conducive to the lightweight design of the battery.

[0058] Please refer to Figure 4As shown, in some embodiments, the connecting portion 131 is spaced apart from the cover plate body 11, and along the thickness direction X, the connecting portion 131 has a thickness dimension T1 mm, satisfying 0.5≤T1≤0.8. It needs to be understood that by spacing the connecting portion 131 apart from the cover plate body 11, good electrical insulation between the two is ensured, and at the same time, space for welding the tab 21 is provided between the connecting portion 131 and the cover plate body 11. By limiting the thickness dimension of the connecting portion 131, it is ensured that it has sufficient mechanical strength when connected with the tab 21 to support part of the tab 21; by fixing the tab 21 and the surface of the connecting portion 131 on the side of the cover plate body 11, the tab 21 can be supported on the connecting portion 131 during assembly without excessive bending, on the one hand, avoiding excessive bending of the tab 21, and the tab 21 no longer bears a large stress due to the excessively bent part, thereby effectively reducing the risk of tearing of the tab 21, prolonging the service life of the battery, and improving the quality and competitiveness of the product. On the other hand, it avoids the problem of occupying too much space by bending the traditional tab 21, effectively improves the utilization rate of the internal space of the battery, and is conducive to realizing the miniaturization and lightweight design of the battery.

[0059] Specifically, T1 can be any value or a range value between two values in 0.5mm, 0.6mm, 0.7mm and 0.8mm. When the thickness of the connecting portion 131 is too thin, it may not be able to withstand the mechanical stress generated by the battery during use, causing the connecting portion to easily break or loosen, affecting the normal work of the battery; while the thickness of the connecting portion 131 is too thick, it may make the connecting portion 131 too bulky, increase the overall weight of the battery, and may cause space interference when assembled with other components and other problems. The appropriate size makes the connecting portion 131 firmly connect the tab 21, and also coordinates with the cover plate body 11, the pole 12 and other components to maintain the stability of the battery structure.

[0060] Please refer to Figure 3 and Figure 4As shown, in some embodiments, the pole 12 includes a first pole body 121 connected to a second pole body 122, the first pole body 121 is located on the side of the cover plate body 11 away from the electrode assembly 2, the second pole body 122 is located between the first pole body 121 and the connecting piece 13, and partially penetrates the assembly hole 110, and the first protrusion 120 is arranged on the side of the second pole body 122 away from the first pole body 121. It should be understood that the first pole body 121 is arranged on the side of the cover plate body 11 away from the electrode assembly 2, and the upper plastic 15 is also clamped between the first pole body 121 and the cover plate body 11, which can play an insulating role, avoiding unnecessary current conduction between the pole 12 and the cover plate body 11, and improving the safety and stability of the battery; at the same time, the upper plastic 15 has a certain elasticity, which can play a buffering role when the battery is subjected to external forces such as vibration and impact, reduce the rigid collision between the pole 12 and the cover plate body 11, protect the battery structure from being damaged, and prolong the service life of the battery. The second pole body 122 partially penetrates the assembly hole 110, on the one hand, it makes full use of the space on the cover plate body 11, making the internal structure of the battery more compact, on the other hand, it effectively prevents the pole 12 from loosening or displacing during the use of the battery, ensuring the stability of the electrical connection, thereby ensuring that the battery can reliably transmit current. The second pole body 122 and the stepped portion 132 can cooperate and press the third sealing segment 143 to fix the local position of the sealing member 14 and ensure that the sealing member 14 reaches a sufficient elastic deformation amount, reducing the assembly error and improving the assembly sealing performance.

[0061] In some embodiments, the first pole body 121 and the second pole body 122 are integrally formed; and / or, the second pole body 122 and the first protrusion 120 are integrally formed. It should be understood that when the first pole body 121, the second pole body 122 and the first protrusion 120 are integrally formed, they can be a positive pole 12 of the same material, or a negative pole 12 of the same material; when only the first protrusion 120 and the second pole body 122 are integrally formed, the first pole body 121 and the second pole body 122 can be a composite assembly, wherein the second pole body 122 can be made of copper, and the first pole body 121 can be made of aluminum.

[0062] The embodiments of the present application also disclose a battery pack comprising the single battery as described in the above embodiments. Therefore, all the technical features and technical effects of the single battery described above can be achieved, and details are not repeated here.

[0063] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0064] The above has carried on the detailed introduction to the single battery and the battery pack provided by the embodiment of the application, and the principle and implementation mode of the application are described by applying specific examples; the above embodiment description is only used to help understand the technical solutions and core ideas of the application; ordinary skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A single cell, characterized by, The cover plate assembly comprises a cover plate body and an electrode assembly arranged on one side of the cover plate body along a thickness direction, and the electrode assembly comprises a tab; The cover plate assembly comprises: a cover plate body having an assembly hole; a post arranged on a side of the cover plate body away from the electrode assembly, the post having a first protrusion protruding into the assembly hole; a connecting piece arranged on a side of the cover plate body facing the electrode assembly, the connecting piece comprising a connecting portion and a stepped portion connected to each other, the connecting portion being connected to the tab, and the stepped portion partially penetrating the assembly hole and being provided with a through hole along the thickness direction; the first protrusion penetrates the through hole and is connected to the stepped portion, and the post and the stepped portion jointly clamp both sides of the cover plate body along the thickness direction.

2. The cell according to claim 1, wherein The stepped portion comprises a first step, a second step and a third step arranged along the thickness direction, the first step penetrating the assembly hole, the third step surrounding the assembly hole and being located on a side of the cover plate body facing the electrode assembly, and the second step surrounding and connecting the first step and the third step; the through hole penetrates the first step, the second step and the third step.

3. The cell according to claim 2, wherein The cover plate assembly further comprises a sealing member comprising a first sealing segment, a second sealing segment and a third sealing segment, the first sealing segment being clamped between the post and the second step, the third sealing segment being clamped between the third step and the cover plate body, and the second sealing segment penetrating the assembly hole and connecting the first sealing segment and the third sealing segment respectively.

4. The cell according to claim 2, wherein The second step partially penetrates the assembly hole, and along the thickness direction, the part of the second step penetrating the assembly hole has a first size H1 mm satisfying 0.5≤H1≤0.

8.

5. The cell according to claim 2, wherein Along the thickness direction, the second step has a second size H2 mm from the post, and the third step has a third size H3 mm from the cover plate body, satisfying 0.5≤H2≤0.7 and 0.5≤H3≤0.

7.

6. The cell according to claim 2, wherein The width direction of the cover plate assembly intersects with the thickness direction, and along the width direction of the cover plate assembly, the first step has a fourth size W1 mm satisfying 2.5≤W1≤5; the second step has a fifth size W2 mm satisfying 5≤W2≤7.

5.

7. The cell according to claim 1, wherein The stepped portion has a first surface facing the electrode assembly and a second surface away from the electrode assembly, the through hole penetrating the first surface and the second surface, and the stepped portion has a relief groove arranged on the first surface and communicating with the through hole; the relief groove has a groove wall opposite to the second surface, and along the thickness direction, the second surface and the groove wall have a minimum distance T mm satisfying 1.2≤T≤1.

8.

8. The cell according to claim 1, wherein The connecting portion is arranged apart from the cover plate body, and along the thickness direction, the connecting portion has a thickness size T1 mm satisfying 0.5≤T1≤0.

8.

9. The cell according to claim 7, wherein The pole post comprises a first post body and a second post body connected to each other, the first post body is located on the side of the cover plate body away from the electrode assembly, the second post body is located between the first post body and the connecting sheet and partially penetrates the assembly hole, and the first protruding part is arranged on the side of the second post body away from the first post body.

10. A battery pack, characterized by, The single battery includes any one of the single batteries according to claims 1 to 9.

Images